Boil the potatoes in salted water. Once cooked mash with 2 oz butter until smooth and creamy.

Simmer the fish with bay leaves, salt and pepper, in milk until the fish flakes easily. Drain and reserve the milk. Flake the fish and put in a baking dish.

Heat oven to 350 degrees F.

In a large saucepan, melt 2 oz butter, cook the shrimp until it turns pink. Remove the shrimp to the baking dish. In the same butter cook onions and celery until soft. Stir in the flour. Gradually pour in the reserved milk stirring constantly until thickened. Season with salt and pepper. Pour the sauce over the fish and shrimp. Top with mashed potatoes. Bake for 20-30 minutes or until the top is golden brown.